Exercising devices generally serve two purposes, to strengthen the muscles and to rehabilitate the muscles. To prevent injuries from occuring to the knee it is important that athletes involved in contact sports strengthen the muscles controlling the knee. The most efficient way to strengthen the muscles in the knee is to isolate the knee muscles from the nest of the body for effective exercising.
Heretofore, devices which are designed to strengthen the knee generally comprise devices having a series of pulleys and ropes for lifting weight. The devices tend to exercise in only a single direction and furthermore cannot be released at any point except the lowermost point of the weight.
Other devices such as those disclosed in U.S. Pat. Nos. 3,120,954; 3,465,592; 3,495,824; and 3,822,599 generally use sophisticated hydraulic structures and pumps which add to the cost and complexity of the device and thereby reduce their availability to the general public.